Conducted in 13 Dutch hospitals between 2004 and 2006, the study involved nearly 6,000 patients. Two groups of patients given antibiotics preventively were 3.5 and 2.9 percent more likely to survive than the control group; the numbers were adjusted, according to a press release for the study, to reflect that “patients in the control group were in general slightly less sick.”

Additionally, patients treated with antibiotics were not more likely to contract antibiotic-resistant bacteria, also known as “superbugs.” According to the press release, “The findings have settled a long-running debate on whether the advantages of using antibiotics as a preventive measure offset the drawback of the possibility of developing antibiotic resistance.”

Other doctors and health experts are skeptical, however. Many hospitals have warned against the overuse of antibiotics because it can lead to a rise in superbugs such as MRSA. Epidemiologist William Jarvis, a former head in the Centers for Disease Control and Prevention Hospital Infections Program, told Scientific American that data from Dutch hospitals—which lead the world in controlling superbugs—may not be relevant for hospitals in the United States and other countries with more serious antibiotic-resistant bacteria problems.

Furthermore, there are still questions about long-term effects of preventive antibiotic use, as the study tracked patients for just 28 days after treatment began. “Anytime you give an antibiotic, you need to be concerned about the emergence of [antibiotic] resistance,” said epidemiologist Neil Fishman to Scientific American. “This study was not big enough and long enough to detect that.”

“Superbugs emerge when an antibiotic fails to kill all of the bacteria it targets, and the surviving bacteria become resistant to that particular drug and frequently other antibiotics as well,” writes the Mayo Clinic. “Doctors then prescribe a stronger antibiotic, but the bacteria quickly learn to withstand the more potent drug as well, perpetuating a cycle in which increasingly powerful drugs are required to treat infections.”

Antibiotics are used to treat bacterial infections, but many patients are prescribed antibiotics for viral infections. Doctors are warned that this overuse or misuse of antibiotics leads to stronger, more resistant strains of bacteria.

It is not clear, however, whether preventive use of antibiotics for bacterial infections creates a rise in antibiotic-resistant bacteria. The Dutch study suggests that preventive use does not have an effect on the spread of superbugs, but its press release states, “The study was too short to be able to provide any insight into how resistance develops in the long term, and this will require further research.”